Add SDK definitions for upstream wasm backend enabled LLVM, "sdk-wasm-master-32/64bit". (#213)

Author: juj

emsdk_manifest.json

@@ -1079,30 +1079,60 @@
     "uses": ["clang-incoming-32bit", "node-8.9.1-32bit", "python-2.7.13.1-32bit", "java-8.152-32bit", "emscripten-incoming-32bit", "binaryen-master-32bit"],
     "os": "win"
   },
+  {
+    "version": "wasm-master",
+    "bitness": 32,
+    "uses": ["upstream-clang-master-32bit", "node-8.9.1-32bit", "python-2.7.13.1-32bit", "java-8.152-32bit", "emscripten-incoming-32bit", "binaryen-master-32bit"],
+    "os": "win"
+  },
   {
     "version": "incoming",
     "bitness": 64,
     "uses": ["clang-incoming-64bit", "node-8.9.1-64bit", "python-2.7.13.1-64bit", "java-8.152-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
     "os": "win"
   },
+  {
+    "version": "wasm-master",
+    "bitness": 64,
+    "uses": ["upstream-clang-master-64bit", "node-8.9.1-64bit", "python-2.7.13.1-64bit", "java-8.152-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
+    "os": "win"
+  },
   {
     "version": "incoming",
     "bitness": 64,
     "uses": ["clang-incoming-64bit", "node-8.9.1-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
     "os": "osx"
   },
+  {
+    "version": "wasm-master",
+    "bitness": 64,
+    "uses": ["upstream-clang-master-64bit", "node-8.9.1-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
+    "os": "osx"
+  },
   {
     "version": "incoming",
     "bitness": 32,
     "uses": ["clang-incoming-32bit", "node-8.9.1-32bit", "emscripten-incoming-32bit", "binaryen-master-32bit"],
     "os": "linux"
   },
+  {
+    "version": "wasm-master",
+    "bitness": 32,
+    "uses": ["upstream-clang-master-32bit", "node-8.9.1-32bit", "emscripten-incoming-32bit", "binaryen-master-32bit"],
+    "os": "linux"
+  },
   {
     "version": "incoming",
     "bitness": 64,
     "uses": ["clang-incoming-64bit", "node-8.9.1-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
     "os": "linux"
   },
+  {
+    "version": "wasm-master",
+    "bitness": 64,
+    "uses": ["upstream-clang-master-64bit", "node-8.9.1-64bit", "emscripten-incoming-64bit", "binaryen-master-64bit"],
+    "os": "linux"
+  },
   {
     "version": "master",
     "bitness": 32,